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https://github.com/golang/go
synced 2024-11-23 18:20:04 -07:00
syscall: eliminate aliasing of syscall error strings in Plan 9
To avoid allocation between entersyscall and exitsyscall in Plan 9, syscall error strings retrieved from the OS were being stored in a shared buffer for each M, leading to overwriting of error strings by subsequent syscalls, and potential confusion if exitsyscall switched to a different M. Instead, the error string is now retrieved to the G stack and then copied to a new allocated array after exitsyscall. A new test TestPlan9Syserr is provided to confirm the correction. Fixes #13770 Fixes #24921 Change-Id: I013c4a42baae80d03a5b61d828396527189f5551 Reviewed-on: https://go-review.googlesource.com/111195 Reviewed-by: David du Colombier <0intro@gmail.com> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org> Run-TryBot: David du Colombier <0intro@gmail.com>
This commit is contained in:
Richard Miller
Brad Fitzpatrick
parent
d148cbe1ec
commit
1b49487692
@ -14,13 +14,16 @@
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//func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2, err uintptr)
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//func RawSyscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr)
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#define SYS_ERRSTR 41 /* from zsysnum_plan9.go */
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// Trap # in AX, args on stack above caller pc.
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TEXT ·Syscall(SB),NOSPLIT,$0-32
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TEXT ·Syscall(SB),NOSPLIT,$148-32
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NO_LOCAL_POINTERS
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CALL runtime·entersyscall(SB)
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MOVL trap+0(FP), AX // syscall entry
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// slide args down on top of system call number
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// copy args down
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LEAL a1+4(FP), SI
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LEAL trap+0(FP), DI
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LEAL sysargs-144(SP), DI
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CLD
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MOVSL
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MOVSL
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@ -31,13 +34,20 @@ TEXT ·Syscall(SB),NOSPLIT,$0-32
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CMPL AX, $-1
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JNE ok3
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SUBL $8, SP
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CALL runtime·errstr(SB)
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MOVL SP, SI
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ADDL $8, SP
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LEAL errbuf-128(SP), AX
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MOVL AX, sysargs-144(SP)
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MOVL $128, sysargs1-140(SP)
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MOVL $SYS_ERRSTR, AX
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INT $64
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CALL runtime·exitsyscall(SB)
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MOVL sysargs-144(SP), AX
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MOVL AX, errbuf-148(SP)
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CALL runtime·gostring(SB)
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LEAL str-144(SP), SI
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JMP copyresult3
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ok3:
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CALL runtime·exitsyscall(SB)
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LEAL ·emptystring(SB), SI
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copyresult3:
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@ -47,15 +57,15 @@ copyresult3:
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MOVSL
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MOVSL
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CALL runtime·exitsyscall(SB)
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RET
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TEXT ·Syscall6(SB),NOSPLIT,$0-44
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TEXT ·Syscall6(SB),NOSPLIT,$148-44
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NO_LOCAL_POINTERS
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CALL runtime·entersyscall(SB)
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MOVL trap+0(FP), AX // syscall entry
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// slide args down on top of system call number
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// copy args down
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LEAL a1+4(FP), SI
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LEAL trap+0(FP), DI
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LEAL sysargs-144(SP), DI
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CLD
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MOVSL
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MOVSL
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@ -69,13 +79,20 @@ TEXT ·Syscall6(SB),NOSPLIT,$0-44
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CMPL AX, $-1
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JNE ok4
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SUBL $8, SP
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CALL runtime·errstr(SB)
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MOVL SP, SI
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ADDL $8, SP
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LEAL errbuf-128(SP), AX
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MOVL AX, sysargs-144(SP)
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MOVL $128, sysargs1-140(SP)
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MOVL $SYS_ERRSTR, AX
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INT $64
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CALL runtime·exitsyscall(SB)
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MOVL sysargs-144(SP), AX
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MOVL AX, errbuf-148(SP)
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CALL runtime·gostring(SB)
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LEAL str-144(SP), SI
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JMP copyresult4
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ok4:
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CALL runtime·exitsyscall(SB)
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LEAL ·emptystring(SB), SI
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copyresult4:
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@ -85,7 +102,6 @@ copyresult4:
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MOVSL
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MOVSL
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CALL runtime·exitsyscall(SB)
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RET
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TEXT ·RawSyscall(SB),NOSPLIT,$0-28
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@ -121,13 +137,23 @@ TEXT ·RawSyscall6(SB),NOSPLIT,$0-40
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MOVL AX, err+36(FP)
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RET
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#define SYS_SEEK 39 /* from zsysnum_plan9_386.go */
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#define SYS_SEEK 39 /* from zsysnum_plan9.go */
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//func seek(placeholder uintptr, fd int, offset int64, whence int) (newoffset int64, err string)
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TEXT ·seek(SB),NOSPLIT,$0-36
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TEXT ·seek(SB),NOSPLIT,$24-36
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NO_LOCAL_POINTERS
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LEAL newoffset+20(FP), AX
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MOVL AX, placeholder+0(FP)
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// copy args down
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LEAL placeholder+0(FP), SI
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LEAL sysargs-20(SP), DI
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CLD
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MOVSL
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MOVSL
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MOVSL
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MOVSL
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MOVSL
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MOVL $SYS_SEEK, AX // syscall entry
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INT $64
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@ -136,10 +162,8 @@ TEXT ·seek(SB),NOSPLIT,$0-36
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MOVL AX, newoffset_lo+20(FP)
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MOVL AX, newoffset_hi+24(FP)
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SUBL $8, SP
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CALL syscall·errstr(SB)
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MOVL SP, SI
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ADDL $8, SP
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JMP copyresult6
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ok6:
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@ -14,12 +14,15 @@
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//func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2, err uintptr)
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//func RawSyscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr)
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TEXT ·Syscall(SB),NOSPLIT,$0-64
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#define SYS_ERRSTR 41 /* from zsysnum_plan9.go */
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TEXT ·Syscall(SB),NOSPLIT,$168-64
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NO_LOCAL_POINTERS
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CALL runtime·entersyscall(SB)
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MOVQ trap+0(FP), BP // syscall entry
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// slide args down on top of system call number
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// copy args down
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LEAQ a1+8(FP), SI
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LEAQ trap+0(FP), DI
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LEAQ sysargs-160(SP), DI
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CLD
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MOVSQ
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MOVSQ
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@ -30,13 +33,20 @@ TEXT ·Syscall(SB),NOSPLIT,$0-64
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CMPL AX, $-1
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JNE ok3
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SUBQ $16, SP
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CALL runtime·errstr(SB)
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MOVQ SP, SI
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ADDQ $16, SP
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LEAQ errbuf-128(SP), AX
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MOVQ AX, sysargs-160(SP)
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MOVQ $128, sysargs1-152(SP)
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MOVQ $SYS_ERRSTR, BP
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SYSCALL
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CALL runtime·exitsyscall(SB)
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MOVQ sysargs-160(SP), AX
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MOVQ AX, errbuf-168(SP)
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CALL runtime·gostring(SB)
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LEAQ str-160(SP), SI
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JMP copyresult3
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ok3:
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CALL runtime·exitsyscall(SB)
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LEAQ ·emptystring(SB), SI
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copyresult3:
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@ -46,15 +56,15 @@ copyresult3:
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MOVSQ
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MOVSQ
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CALL runtime·exitsyscall(SB)
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RET
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TEXT ·Syscall6(SB),NOSPLIT,$0-88
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TEXT ·Syscall6(SB),NOSPLIT,$168-88
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NO_LOCAL_POINTERS
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CALL runtime·entersyscall(SB)
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MOVQ trap+0(FP), BP // syscall entry
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// slide args down on top of system call number
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// copy args down
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LEAQ a1+8(FP), SI
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LEAQ trap+0(FP), DI
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LEAQ sysargs-160(SP), DI
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CLD
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MOVSQ
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MOVSQ
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@ -68,13 +78,20 @@ TEXT ·Syscall6(SB),NOSPLIT,$0-88
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CMPL AX, $-1
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JNE ok4
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SUBQ $16, SP
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CALL runtime·errstr(SB)
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MOVQ SP, SI
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ADDQ $16, SP
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LEAQ errbuf-128(SP), AX
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MOVQ AX, sysargs-160(SP)
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MOVQ $128, sysargs1-152(SP)
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MOVQ $SYS_ERRSTR, BP
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SYSCALL
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CALL runtime·exitsyscall(SB)
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MOVQ sysargs-160(SP), AX
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MOVQ AX, errbuf-168(SP)
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CALL runtime·gostring(SB)
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LEAQ str-160(SP), SI
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JMP copyresult4
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ok4:
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CALL runtime·exitsyscall(SB)
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LEAQ ·emptystring(SB), SI
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copyresult4:
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@ -84,7 +101,6 @@ copyresult4:
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MOVSQ
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MOVSQ
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CALL runtime·exitsyscall(SB)
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RET
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TEXT ·RawSyscall(SB),NOSPLIT,$0-56
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@ -120,24 +136,32 @@ TEXT ·RawSyscall6(SB),NOSPLIT,$0-80
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MOVQ AX, err+72(FP)
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RET
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#define SYS_SEEK 39 /* from zsysnum_plan9_amd64.go */
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#define SYS_SEEK 39 /* from zsysnum_plan9.go */
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//func seek(placeholder uintptr, fd int, offset int64, whence int) (newoffset int64, err string)
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TEXT ·seek(SB),NOSPLIT,$0-56
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TEXT ·seek(SB),NOSPLIT,$48-56
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NO_LOCAL_POINTERS
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LEAQ newoffset+32(FP), AX
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MOVQ AX, placeholder+0(FP)
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// copy args down
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LEAQ placeholder+0(FP), SI
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LEAQ sysargs-40(SP), DI
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CLD
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MOVSQ
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MOVSQ
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MOVSQ
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MOVSQ
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MOVSQ
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MOVQ $SYS_SEEK, BP // syscall entry
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SYSCALL
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CMPL AX, $-1
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JNE ok6
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MOVQ $-1, newoffset+32(FP)
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MOVQ AX, newoffset+32(FP)
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SUBQ $16, SP
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CALL syscall·errstr(SB)
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MOVQ SP, SI
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ADDQ $16, SP
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JMP copyresult6
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ok6:
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@ -5,58 +5,87 @@
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#include "textflag.h"
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#include "funcdata.h"
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#define SYS_ERRSTR 41 /* from zsysnum_plan9.go */
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#define SYS_SEEK 39 /* from zsysnum_plan9.go */
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// System call support for plan9 on arm
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TEXT sysresult<>(SB),NOSPLIT,$12
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MOVW $·emptystring+0(SB), R2
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//func Syscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err ErrorString)
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TEXT ·Syscall(SB),NOSPLIT,$144-32
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NO_LOCAL_POINTERS
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BL runtime·entersyscall(SB)
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MOVW $a1+4(FP), R0 // move syscall args
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MOVW $sysargs-144(SP), R1
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MOVM.IA (R0), [R2-R4]
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MOVM.IA [R2-R4], (R1)
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MOVW trap+0(FP), R0 // syscall num
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SWI $0
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MOVW $0, R2
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MOVW $r1+16(FP), R3
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MOVM.IA [R0,R2], (R3)
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CMP $-1, R0
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B.NE ok
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MOVW R1, save-4(SP)
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BL runtime·errstr(SB)
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MOVW save-4(SP), R1
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MOVW $err-12(SP), R2
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ok:
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B.EQ syscallerr
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BL runtime·exitsyscall(SB)
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MOVW $·emptystring+0(SB), R2
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B syscallok
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syscallerr:
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MOVW $errbuf-128(SP), R2
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MOVW $128, R3
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MOVM.IA [R2,R3], (R1)
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MOVW $SYS_ERRSTR, R0
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SWI $0
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BL runtime·exitsyscall(SB)
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BL runtime·gostring(SB)
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MOVW $str-140(SP), R2
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syscallok:
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MOVW $err+24(FP), R1
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MOVM.IA (R2), [R3-R4]
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MOVM.IA [R3-R4], (R1)
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RET
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//func Syscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err ErrorString)
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TEXT ·Syscall(SB),NOSPLIT,$0-32
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BL runtime·entersyscall(SB)
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MOVW trap+0(FP), R0 // syscall num
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MOVM.IA.W (R13),[R1-R2] // pop LR and caller's LR
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SWI $0
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MOVM.DB.W [R1-R2],(R13) // push LR and caller's LR
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MOVW $0, R2
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MOVW $r1+16(FP), R1
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MOVM.IA.W [R0,R2], (R1)
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BL sysresult<>(SB)
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BL runtime·exitsyscall(SB)
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RET
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//func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err ErrorString)
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// Actually Syscall5 but the rest of the code expects it to be named Syscall6.
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TEXT ·Syscall6(SB),NOSPLIT,$0-44
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TEXT ·Syscall6(SB),NOSPLIT,$144-44
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NO_LOCAL_POINTERS
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BL runtime·entersyscall(SB)
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MOVW $a1+4(FP), R0 // move syscall args
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MOVW $sysargs-144(SP), R1
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MOVM.IA (R0), [R2-R6]
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MOVM.IA [R2-R6], (R1)
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MOVW trap+0(FP), R0 // syscall num
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MOVM.IA.W (R13),[R1-R2] // pop LR and caller's LR
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SWI $0
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MOVM.DB.W [R1-R2],(R13) // push LR and caller's LR
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MOVW $0, R1
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MOVW $r1+28(FP), R1
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MOVM.IA.W [R0,R2], (R1)
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BL sysresult<>(SB)
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MOVW $0, R2
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MOVW $r1+28(FP), R3
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MOVM.IA.W [R0,R2], (R3)
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CMP $-1, R0
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B.EQ syscall6err
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BL runtime·exitsyscall(SB)
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MOVW $·emptystring+0(SB), R2
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B syscall6ok
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syscall6err:
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MOVW $errbuf-128(SP), R2
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MOVW $128, R3
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MOVM.IA [R2,R3], (R1)
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MOVW $SYS_ERRSTR, R0
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SWI $0
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BL runtime·exitsyscall(SB)
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BL runtime·gostring(SB)
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MOVW $str-140(SP), R2
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syscall6ok:
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MOVW $err+36(FP), R1
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MOVM.IA (R2), [R3-R4]
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MOVM.IA [R3-R4], (R1)
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RET
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//func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2, err uintptr)
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TEXT ·RawSyscall(SB),NOSPLIT,$0-28
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TEXT ·RawSyscall(SB),NOSPLIT,$12-28
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MOVW $a1+4(FP), R0 // move syscall args
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MOVW $sysargs-12(SP), R1
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MOVM.IA (R0), [R2-R4]
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MOVM.IA [R2-R4], (R1)
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MOVW trap+0(FP), R0 // syscall num
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MOVM.IA.W (R13),[R1] // pop caller's LR
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SWI $0
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MOVM.DB.W [R1],(R13) // push caller's LR
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MOVW R0, r1+16(FP)
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MOVW R0, r2+20(FP)
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MOVW R0, err+24(FP)
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@ -64,27 +93,40 @@ TEXT ·RawSyscall(SB),NOSPLIT,$0-28
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//func RawSyscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr)
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// Actually RawSyscall5 but the rest of the code expects it to be named RawSyscall6.
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TEXT ·RawSyscall6(SB),NOSPLIT,$0-40
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TEXT ·RawSyscall6(SB),NOSPLIT,$20-40
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MOVW $a1+4(FP), R0 // move syscall args
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MOVW $sysargs-20(SP), R1
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MOVM.IA (R0), [R2-R6]
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MOVM.IA [R2-R6], (R1)
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MOVW trap+0(FP), R0 // syscall num
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MOVM.IA.W (R13),[R1] // pop caller's LR
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SWI $0
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MOVM.DB.W [R1],(R13) // push caller's LR
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MOVW R0, r1+28(FP)
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MOVW R0, r2+32(FP)
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MOVW R0, err+36(FP)
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RET
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//func seek(placeholder uintptr, fd int, offset int64, whence int) (newoffset int64, err string)
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TEXT ·seek(SB),NOSPLIT,$0-36
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MOVW $newoffset_lo+20(FP), R5
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MOVW R5, placeholder+0(FP) //placeholder = dest for return value
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TEXT ·seek(SB),NOSPLIT,$20-36
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NO_LOCAL_POINTERS
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MOVW $newoffset_lo+20(FP), R6
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MOVW R6, sysargs-20(SP) // dest for return value
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MOVW $fd+4(FP), R0 // move syscall args
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MOVW $sysarg1-16(SP), R1
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MOVM.IA (R0), [R2-R5]
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MOVM.IA [R2-R5], (R1)
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MOVW $SYS_SEEK, R0 // syscall num
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MOVM.IA.W (R13),[R1] // pop LR
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SWI $0
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MOVM.DB.W [R1],(R13) // push LR
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CMP $-1, R0
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MOVW.EQ R0, 0(R5)
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MOVW.EQ R0, 4(R5)
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B.EQ seekerr
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MOVW $·emptystring+0(SB), R2
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B seekok
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seekerr:
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MOVW R0, 0(R6)
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MOVW R0, 4(R6)
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BL ·errstr(SB)
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MOVW $ret-20(SP), R2
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seekok:
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MOVW $err+28(FP), R1
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BL sysresult<>(SB)
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MOVM.IA (R2), [R3-R4]
|
||||
MOVM.IA [R3-R4], (R1)
|
||||
RET
|
||||
|
||||
53
src/syscall/syscall_plan9_test.go
Normal file
53
src/syscall/syscall_plan9_test.go
Normal file
@ -0,0 +1,53 @@
|
||||
// Copyright 2018 The Go Authors. All rights reserved.
|
||||
// Use of this source code is governed by a BSD-style
|
||||
// license that can be found in the LICENSE file.
|
||||
|
||||
package syscall_test
|
||||
|
||||
import (
|
||||
"syscall"
|
||||
"testing"
|
||||
)
|
||||
|
||||
// testalias checks for aliasing of error strings returned by sys1 and sys2,
|
||||
// which both call the function named fn in package syscall
|
||||
func testalias(t *testing.T, fn string, sys1, sys2 func() error) {
|
||||
err := sys1().Error()
|
||||
errcopy := string([]byte(err))
|
||||
sys2()
|
||||
if err != errcopy {
|
||||
t.Errorf("syscall.%s error string changed from %q to %q\n", fn, errcopy, err)
|
||||
}
|
||||
}
|
||||
|
||||
// issue 13770: errors cannot be nested in Plan 9
|
||||
|
||||
func TestPlan9Syserr(t *testing.T) {
|
||||
testalias(t,
|
||||
"Syscall",
|
||||
func() error {
|
||||
return syscall.Mkdir("/", 0)
|
||||
},
|
||||
func() error {
|
||||
return syscall.Mkdir("#", 0)
|
||||
})
|
||||
testalias(t,
|
||||
"Syscall6",
|
||||
func() error {
|
||||
return syscall.Mount(0, 0, "", 0, "")
|
||||
},
|
||||
func() error {
|
||||
return syscall.Mount(-1, 0, "", 0, "")
|
||||
})
|
||||
// originally failed only on plan9_arm
|
||||
testalias(t,
|
||||
"seek",
|
||||
func() error {
|
||||
_, err := syscall.Seek(0, 0, -1)
|
||||
return err
|
||||
},
|
||||
func() error {
|
||||
_, err := syscall.Seek(-1, 0, 0)
|
||||
return err
|
||||
})
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user